Fig 1.
Map showing sample sites of the fiddler crab Austruca occidentalis from the Western Indian Ocean (partial mitochondria cytochrome oxidase subunit I (COI) sequences and microsatellites).
The white filled circles represent natural mangroves and black filled circles represent mangroves at salt ponds. The East African Coast Current (EACC) is indicated by black arrows.
Table 1.
Characteristics of primers used for microsatellites analysis in Austruca occidentalis from Tanzania, Western Indian Ocean.
The superscripts a, b, and c at each locus indicate the source of each primer pair.
Fig 2.
Genetic diversity in the fiddler crab Austruca occidentalis from natural mangroves (whitefilled bars) and mangroves at salt ponds (black filled bars) in Tanzania, Western Indian Ocean.
A: Nucleotide diversity and B: haplotype diversity.
Fig 3.
Haplotype network of partial mitochondrial cytochrome oxidase subunit I (COI) sequences from the fiddler crab Austruca occidentalis in Tanzania, Western Indian Ocean.
The central circle in the haplotype network is representing 241 individuals. The size of other circles corresponds to the number of individuals as indicated in the right side of the haplotype network. The haplotype network indicates percentage of haplotypes from natural mangroves (white) and mangroves at salt ponds (black).
Table 2.
Distribution of cytochrome oxidase subunit I (COI) haplotypes of the fiddler crab Austruca occidentalis in Tanzania, Western Indian Ocean at natural mangrove sites and salt pond sites; N: number of individuals; Nh: number of haplotypes at each site; HN: total number of haplotypes for natural mangrove sites; HS: total number of haplotypes for salt pond sites;.N and.S are the codes for natural mangrove and salt pond sites respectively.
Table 3.
Genetic diversity in the fiddler crab Austruca occidentalis from sites at natural mangroves and salt ponds in Tanzania, Western Indian Ocean based on microsatellites.
N: sample size; Na: number of different alleles; Ae: mean effective number of alleles; I: Shannon's information index; Ho: observed heterozygosity; uHe: unbiased expected heterozygosity; PA: number of private alleles; Fis: inbreeding coefficient, Ar: Allelic richness;.N and.S are the codes for natural mangrove and salt pond sites respectively.
Fig 4.
Principal coordinates analysis (PCoA) indicating population genetic differentiation based on pairwise Fst-values in the fiddler crab Austruca occidentalis from Tanzania, Western Indian Ocean.
: A) COI sequences and B) microsatellites. Circles represent salt ponds and triangles natural mangroves. (TN, BN, KN, LN, MN, PN, UN) and (TS, BS, KS, LS, MS, PS, US) represent Tanga, Bagamoyo, Kilwa, Lindi, Mtwara, Pemba and Unguja natural mangroves and salt ponds sites, respectively. The percentage of variation is mainly explained by the first axis. For sequences data is 91.89% and for microsatellites data is 31.74%.
Table 4.
Pairwise Fst-values for cytochrome oxidase subunit I (COI) sequence data (bellow diagonal) and microsatellites (above diagonal) in the fiddler crab Austruca occidentalis from Tanzania, Western Indian Ocean; .N and .S are the codes for natural mangrove and salt pond sites respectively.
Fig 5.
The observed (bars) and expected (line) frequency of pairwise differences of cytochrome oxidase subunit I sequences from the fiddler crab Austruca occidentalis in Tanzania, Western Indian Ocean.
A. Populations from natural mangroves and B. populations from mangroves at salt ponds.
Table 5.
Demographic and neutrality parameters based on cytochrome oxidase I (COI) sequences from the fiddler crab Austruca occidentalis from Tanzania, Western Indian Ocean.
SSD: sum of squared deviations, HRI: Harpending’s raggedness index, D: Tajima’s D and Fs: Fu’s Fs,.N and.S are the codes for natural mangrove and salt pond sites respectively.
Table 6.
Estimated effective population size and migration rate based on microsatellite data using the programs MIGRATE (mean and 95% confidence interval) and BayesAss (mean and standard deviation) in the fiddler crab Austruca occidentalis from Tanzania, Western Indian Ocean.
Θ: mutation-scaled population size; m: pairwise migration (± standard deviation);.N and.S are the codes for natural mangrove and salt pond sites respectively.